Arsenal's laboured win at Fulham shows need to build on foundations

Fans hope that frantic victories such as this will serve the twin aims of qualifying for the Champions League while convincing Arsène Wenger and the club's directors that investment in more high-calibre players is needed if next season is to be more comfortable. But the fear lingers that, if Arsenal do cling on to their top-four place, even with as much difficulty as they hung on for this win against a depleted Fulham, then the board could consider that no revamp is required. Hence some supporters believe that the shock of missing out on the Champions League would ultimately be more instructive than wins like this.

There is a debate, then, as to whether Arsenal's recent run of good results is the work of a side that is papering over cracks or laying a foundation for long-term success. Arsenal's goal at Craven Cottage contained a clue or two, simultaneously highlighting a lack of creativity and a partnership that is working well.

It was fitting that it came from interplay between Arsenal's centre-backs, Laurent Koscielny heading across the face of goal for Per Mertesacker to nod in, because they have epitomised the resilience and determination that have enabled Arsenal to amass 19 points from the last 21 available. Those qualities were crucial here, as Fulham frightened Arsenal despite being reduced to 10 men after Steve Sidwell was sent off in the 12th minute, and Arsenal lacked imagination and sharpness in the opposing box, just as they had done against Everton in midweek.

The recent displays of Mertesacker and Koscielny have vindicated Wenger's decision to drop the club captain, Thomas Vermaelen, who had developed an alarming habit of making mistakes. Without making a direct comparison between his two potential partners, Koscielny says he feels comfortable with Mertesacker. "We play well together as a pair," he says.

"His experience is vital and it helps us work together on the pitch. So we try and talk to each other a lot and it is important at the back to have an understanding …Per is a very good player. He reads the ball well. He is clever. He attacks the ball and wins headers whereas I can go behind and be quick and cope with the long balls. He is good technically so he is good for the defence. Per is calm on the pitch. He is good for me and uses his experience and this helps me and he helps the team."

The home match against Manchester United on Sunday may prove a useful benchmark as to how reliable Koscielny and Mertesacker can continue to be. They seem certain to start that game even if Wenger maintains that he has "three outstanding centre-backs" and it is "a very difficult decision" as to whether to omit Vermaelen again.

A more difficult decision is to be made further forward, as Olivier Giroud will miss United's visit after being sent off in the last minute at Craven Cottage for a clumsy tackle on Stanislav Manolev.

The Frenchman has hardly dazzled lately but none of his potential replacements has convinced either. Theo Walcott was irrelevant on the right against Fulham and has not been effective often enough at centre-forward to make his deployment there a foregone conclusion. Gervinho is equally inconsistent and Wenger does not seem to have total trust in Lukas Podolski, who has completed 90 minutes only twice in the Premier League all season.

"I will make a decision later in the week," said Wenger of his striker dilemma. He is more sure of the participation of Jack Wilshere. The 21-year-old was rested against Fulham as he continues to work his way back from ankle trouble and there are reports that he could require surgery in the summer to replace a pin inserted into his ankle following his initial injury in 2011, but the manager says the player will be available next week.

"I just felt to give him three games in six days would be too much. Now he has a break until next Sunday and that is different so he will be available. There is no basic ankle problem."